The political history of the Thar has largely been understood through the history of its political segments Jaisalmer, Jodhpur and Bikaner. As these states were assimilated into the Mughal Empire in the late sixteenth century, the study of polity in this region largely became the study of Mughal-Rajput dynamics. However, as we saw in the previous chapter, Thar was a fluid mobile region, geographically, economically, culturally, as well as politically. Munhata Nainsi's imagination of a ‘Rajput’ political history in the seventeenth century, revealed a fluid polity that relied on kin and clan relationships operating across the Thar through martial and marital alliances. However, by the nineteenth century, the political geography of this region was increasingly understood through the idea of boundaries, rather than frontiers. The subsidiary alliances between Rajput states and the British in early nineteenth century accentuated the binary between the idea of boundary and frontier. While the boundary became the site of legitimate political endeavors, the frontier became the ‘outlawed’ space. Frontiers were often contested non-agrarian terrains like hills, forests or deserts that increasingly came to be seen as hostile spaces by the nineteenth century. But frontiers were also spaces where complex political processes led to redefinition of social and political identities. As the previous chapter explored the idea of Thar as a geographical frontier, this chapter examines the idea of Thar as a political frontier. It seeks to examine the idea of the Thar as a frontier defined through the mobility of its travelers and the relationship of this mobility with political control. It puts forth the argument that the Thar, for several centuries, had been a site for complex political negotiations, where authority was defined through control over access to mobile resources, whether pastoral wealth or trade. By the nineteenth century, discomfort with multiple levels of control led to certain kinds of controls being rendered legitimate and others illegitimate.